I just read a recent News article about human evolution: M. Balter, "Are human
brains still evolving? Brain genes show signs of selection", Science 309 (2005),
1662-1663. My quotations in the following are from Balter's comments. Two
studies "led by human geneticist Bruce Lahn of the University of Chicago"
[Science 309 (9 Sept. 2005), p. 1717 and 1720] "conclude that two genes thought
to regulate brain growth have continued to evolve under natural selection until
very recently". I haven't yet read the two original articles, but wanted to ask
for your comments now.

"Lahn's group focused on two genes, ... microcephalin and ASPM", mutations in
which "cause microcephaly, in which the brain is severely reduced in size." Both
genes "have come under strong natural selection since the chimp-human split" ~6
Ma ago. Sequencing the two genes in 90 human cell lines provided "evidence that
selection had operated on [them] much more recently - since the rise of modern
humans." For both genes, one of their alleles occurs at "surprisingly high
frequency ... unlikely to be due to random genetic drift or population migration".

In this way, the origin of the favored microcephalin allele has been dated "at
37,000 years ago (with confidence intervals ranging from 14,000 to 60,000 years)
- about the time of the explosion of symbolic behavior in Europe." Might this
correspond to the time when humans were created in God's image (Gen.1:27)?

ASPM stands for "abnormal spindle-like microcephaly associated" [J. Zhang,
"Evolution of the human ASPM gene, a major determinant of brain size", Genetics
165 (2003), 2063-2070]. Two years ago, Zhang suggested that ASPM's positive
selection had occurred earlier than 100,000 years ago and was connected with the
human brain expansion between ~2 and ~0.3 My ago.

Lahn's new study suggests the allele of the ASPM gene prevalent today "arose
5800 years ago (with a possible range of 500 to 14,100 years), just before
cities arose in the Near East." This sounds suspiciously close to the time for
Adam, as deduced from the cultural indications of the early Genesis chapters.

"Lahn's team argues that in the case of ASPM in particular, the young age of the
selected allele and its worldwide distribution suggests that it was subject to a
strong Â«selective sweepÂ» in the very recent past. Lahn says these alleles may
have provided an adaptive advantage, possibly although not necessarily
cognition." An advantage in cognition arising this recently sounds preposterous.

I don't expect any scientific proof of these two fixpoints in the biblical
account on human origins - Gen.1:27 and 2:7 -, but there might be a good
complementarity. What's your opinion?